King County Interbay Pump Station Upgrade

Project overview

Vanir provided construction management services for the Interbay Pump Station Upgrade, which increased the station’s pumping capacity from 122- 133 million gallons per day, was completed ahead of schedule with a low change order rate. The team provided technical engineering expertise, schedule review and analysis, RFI/submittal/document control and change management. Construction had to be performed while maintaining the 24/7 operation. The team worked collaboratively with King County Operations staff to schedule and coordinate the work efficiently, which included:

  • Removal and replacement of the three existing 36-inch raw sewage pumps and drives with new pumps with high-efficiency motors on variable frequency drives
  • Removal and replacement of the 36-inch steel discharge piping within the building and reinstallment of the four existing 36-inch ball valves
  • Structural modifications to the existing structure
  • Mechanical work including a utility water pump, nonpotable water pumps, an instrument air compressor and sump pumps
  • Electrical work including replacement of the existing 4,160 volt and 480 volt switchgear, construction of a generator building and the purchase and installation of one 4,160 volt generator
  • HVAC work including replacement of fans and air ducts, the addition of a heat pump and unit heaters and the installation of an on-site odor control unit
  • Replacement of the existing bridge crane and installation of a new hoist
Seattle, Washington
King County



Stellar J Corporation

Construction Cost
$12 Million
Start Date
Completion Date